Kilroy's stoking indicators


Mar 22, 2003
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I think the system was quite simple. Each double-ended boiler had three furnaces per face: 1, 2, and 3. Each boiler face was worked by one fireman. There were 10 firemen per boiler room, 5 per stokehold, in BRs 2, 3, 4, and 5; and 8 firemen, 4 per stokehold, for BR 6. (Not counting 1 leading fireman per BR, and 2 trimmers per stokehold.)
The duplex indicator dial for a given stokehold showed the furnace number to be fired on each boiler face in that stokehold. The dial cycled through 1-2-3, 1-2-3, ... changing one cycle per firing rate period determined by what was set on the regulator in the engine room. On the other side of a double-ended boiler, the indicator there would cycle through 2-1-3, 2-1-3, ... in step with the changes in the opposite stokehold, being worked off of the same regulator in the engine room. Thus, opposite ends of the same furnace on a double-ended boiler would never be opened at the same time.
DEboiler.gif
 
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Lars Lunden

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Lars I guess you're the one that posted the picture, so you've seen it... Sometimes when I'm using my phone to use this site it doesn't show everything. lol :rolleyes:. However, still interested in your thoughts.

Yes, it was me who posted :p.

From the sources found I can only think there was 3 numbers on Titanic. (I'm still looking if there is more information to be found) The Evershed & Vignoles catalogues also show the furnaces to be numbered [1] [3] [2] on the boilers.

From multiple stoking manuals, however, I've not been able to find any information on which direction to stoke double-end boilers. I think the most fale-safe is to stoke in the same direction in both stokeholds. Remember - there is also a delay between the two stokeholds; one will always be ahead of the other. This will also make raking easy.
In the lowest time setting on the regulator, 480 sec, each of the numbers are visible in 160 sec and you will have a 80 sec delay between the stokeholds.

I will attach an illustration i'm drafting my thoughts on.
Black numbers = The brass or malleable numbers fitted on the boilers
Red numbers = The order which the furnaces are to be fired

When "Fire Furnace No. 1" all # 1 doors are fired, but not at the same time to prevent more than one door open at the same time.
titanic-stoking-1-jpg.jpg


Titanic stoking 1.jpg
 
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B-rad

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I believe you've out done yourself my friend, fantastic article and easy to read and understand. Did you draw the wiring diagram? I can't blow it up enough to read the print. I believe your research would be a great addition to future publications of Titanic the Ship Magnificent! (never mind, got it to finally blow up big enough, just wanted to be stubborn.)
 
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Lars Lunden

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Thanks. Yes i have drawn the wiring diagram myself. I have attached a better quality of it. It has been fun researching. Who knows. Maybe there is more to be found.
Wonder if all have been scrapped or if there is any indicators who have survived; it was used on many different ships.

Olympic and Titanic used the same type; a single gong duplex indicator. But I wonder if Britannic was installed with the improved Duplex indicator; like the one pictured in your post # 31 of SS Justicia.
 

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Rancor

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When "Fire Furnace No. 1" all # 1 doors are fired, but not at the same time to prevent more than one door open at the same time.

Do you know how they judged the timing for each individual boiler? Was it a matter of when the gong sounded say the port most boiler had its furnace fired, with the stoker for the next boiler watching until the firing was complete and then firing his furnace in turn?
 

Lars Lunden

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Yes. I think the leading fireman would make sure they keep the pace. Here is an example from Engine-room practice, a handbook for the royal navy and mercantile ,marine, 1906. p. 344 It shows an illustration of three boilers each having four furnace doors each. «The number "One" fires of all the boilers to be fired in rapid succession one after the other, one door only to be open at a time - two and a half minutes afterwards the number "Two" fires in all the boilers to be fired in rapid succession; two and a half minutes after that, the number "Three" openings, and so on. This may be conveniently arranged with a clock in each firing-room- each clock set a little in advance of the other, so as to have as few fire-doors as possible open at one time»

I do not know the average time to fire a furnace, but on the lowest setting of 8 minutes and with five furnaces to be fired in succession, the firemen on Titanic will have to fire each furnace in 32 seconds. If not, they're in serious trouble as the indicator will show a new number before all furnaces are finished.
 
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Rancor

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It's been a while, but I found this, thought you might like it.View attachment 48282

Interesting, those boilers definitely don't look like Scotch boilers.

I do not know the average time to fire a furnace, but on the lowest setting of 8 minutes and with five furnaces to be fired in succession, the firemen on Titanic will have to fire each furnace in 32 seconds. If not, they're in serious trouble as the indicator will show a new number before all furnaces are finished.

32 seconds seems a bit fast. Is it possible that when the gong sounded each fireman fired one furnace per boiler all at the same time? For example when '1' showed every fireman fired furnace number 1 on their respective boiler together?
 
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Lars Lunden

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They where most likely fired in succession, having read different engine/boiler room books.

From the book "Engine room practice" 1906, p. 329:

Illustration of 4 boilers each having 4 furnace doors.

"At the first ring all furnace doors numbered 1 are fired through in succession with (b) shovelsdul of coal each, commensing with No. 1 door at the left hand side of the stokehold and going to each No. 1 door from left to right, across or along the stokehold until all No. 1 furnace doors have been fired through, care being taken that there should never be more than one furnace door open at a time. At the next ring all No 2 doors are fired through [...]"

I don't have the knowledge to answer if 32 seconds, at the fastest rating, is to short time or not to fire a furnace.
 
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Tim Aldrich

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I'm not so sure about 32 seconds being too short of an interval. If an average bloke, like me or you, was doing the job 32 seconds would be too quick. For experienced fireman 32 seconds seems quite normal.

One must think of the process. Some sort of notification would happen and...

-Fireman unlatches and opens the furnace door with his shovel
-Coal (already at the fireman's feet and broken into more useful chunks thanks to the trimmers) is loaded into the shovel.
-Fireman looks at the bed of coals (which isn't the actual fire) and knows, by color, where that shovelful of coal needs to go.
-Fireman slings that coal (with accuracy) into the furnace.
-During that time the fireman had already noticed the dark spots which indicated clinkers.
-The fireman grabs the "devil's tail" (devil's bar, devil's hook... the actual name escapes me at the moment) and breaks up the clinkers to a small enough size that they'll fall through the grates into the ash pit.
-The fireman will then rake the coals as necessary to provide an even fire.
-The furnace door is then shut.

If you memorize that process, assuming you already have an understanding of boilers, furnaces, grates etc., and then start a timer for 32 seconds, you'll be able to see that that interval is not out of the ordinary. That said, I would love to see the gear train that was used to time the whole process. Mechanical computing at (almost, the fire control computers about WWII Iowa class battleships being the zenith) it's near best.
 
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Lars Lunden

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Very nice indeed!
I have seen a photo somewhere of a stoking indicator at the wreck of Britannic. But I can't find it. I belive Britannic used a different indicator than Olympic and Titanic - an improved version of the duplex indicator. This version used an interrupter circuit to make the gong repeat itself 4 times for every new number on the indicator. If I could find the photo, I would be able to confirm this.
 

Lars Lunden

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The photo can be seen on p. 422 in Simon Miller's book, Exploring the Britannic, 2019. A stoking indicator with a seperate compartement for the gong.
This confirms another difference between Britannic and her sisters.
 
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